Roasting-furnace.



No. 768,748. l PATENTED AUG. so, 1904. o. HOFMANN.

ROASTING PURNACE.

APPLICATION FILED AUG. 29. 1903.

No MODEL. a SHEETS-SHEET 1.

PATENTED AUG. so, 1904. o. HOFMANN. l ROASTING FURNACE. APPLICATION FILED AUG. 29. 1903.

3 SHEETS-SHEET 2.

N0 MODEL.

PATENTED AUG. 30,1904,

O. HOPMANN. ROASTING FURNAGE. APPLICATION FILED AUG. 29. 190s. No MODEL. a SHEETS-SHEET 3,

x Hornet@ No. 768,748. Patented August 30, 1904.

UNiTnD STATES PATENT Orricn.

rOTTOKAR HOFMANN, OE ARGENTTNE, KANSAS, ASSTGNOR TO THE UNTTED ZTNC AND CHEMICAL COMPANY, OF KANSAS CTTY, MISSOUR, A OOR- PORATION OE NEW JERSEY.

ROASTlNGi-FURNAOE.

SPECFICATION forming part of Letters Yatent No. 768,748, dated August 30, 1904. Application filed August 29, 1903. Serial No. 171,238. (No model.)

To (L7/7,

Be it known that l, OrroitAR Hermann, a citizen of the United States, residing at Argentine, in the county of Vyandotte and State of Kansas, have invented certain new and useful Improvements in Roasting-Furnaces, of which the following is a speci wfwm 77W!! 00m-307% l of the work, and consequently with great loss of time and money. Tt is therefore desirable in constructing such i vide for good cooling of the central shaft', second, to provide for an eiiicient cooling of the stirring-arms, and, third, to construct the attachment of the stirring-arms to the cenfication.

constructed -io The furnaces of this class are so iron shell which that in a cylindrical steel or is lined with bricks roasting-shelves are arranged one above the other, through the center of which a hollow shaft is inserte To this shaft rakes or stirring-arms are attached corresponding to the different shelves, by means of which the ore is not only stirred,

fective arm.

My invention relates principally to improvements in the apparatus indicated or outlined in the above-enumerated three points, and I believe it to constitute a decided advance on the art of constructing roasting-furnaces.

Tn the accompanying drawings, Figure l but also moved so that it gradually drops represents a vertical section through the cenfrom one shelf to the other until it is autoter of the furnace, and Fig. 2 a top view o' 2o matically discharged from the last shelf. These the same. ig. 5 is a cross-section, and ig. furnaces are mostly used for roasting highlyi a vertical section, through the tubular shaft sulfureted ore, like iron pyrites, where the S, showing the sockets for the stirring-arms. roasting is principally performed for the pur- Fie". 5 is an outside view, and ig. 6 an inside U pose of utihZinO the produced sulfurous-acic view, illustrating the sockets for the stirringgas for the manufacture of sulfuric acid, 0r

arms. ig. 7 is an enlarged plan, and Fig. 8 for roasting Zinc-blende ore for the double an enlarged sectional view, of the upper end purpose of using the gas to make sulfuric acid of the tubular shaft; and Fig. 9 is an enlargeand the cinders for the manufacture of spelter.

of a portion of Eig. 8

Then used for Zinc ore, more roasting-shelves aic requirec of which some of the lower ones The furnace as represented is arranged for roasting ores like Zine-blende, which require have to be muffled to permit the application of additional heat by means of a specia fire additional heat for completing the roast, and is therefore provided with more roastingivithout allowing the fuel combustion-gases shelves AAA A than are usually found in a to mix with the roasting-gases. As the cenfurnace of that type, of which the three lower 3 5 tral shaft of the furnace, as well as the stirones can receive additional heat by the three ring-,arms which are attached to the former are made of iron and iron is readily attacked inserted fire-flue chambers B The central hollow shaft S is provided with a number by sulfur when red-hot and also warps hen exposed to higher heat, it is apparent that of recesses C C, two of which always correspond in 'their vertical location with the loca- 40 these costly iron parts wi l be of short duration of one of the roasting-shelves. They are tion if not properly cooled. The stirringarms are the parts most exposed to the deplaced diametrically opposite and serve for the insertion of the stirring-arms W. Their stroying infiuence, and the operator is obliged it is of position, however, in relation to the different to renew them from time to time, and

roasting- `helves is so thatthe arms in every great importance that this should be done succeeding shelf are horizontally at right quickly without cooling down the furnace, as

angles with the arms of the preceding one,'so this would be connected with an interruption that the ore dropping rom one shelf to the furnaces, first, to pro- My invention relates to that class of roasttral shaft in such a way as to permit a quick ing furnaces known as the McDougall type. and easy withdrawing and replacing of the de- `is made, the lugs come to rest against the means of bolts X; but in order to permit th replacement of an old sleeve by a new one ii case this should be required without cooling of the iron tie furnace the bolts are of a peculiar shape other docs not strike the rake. The recesses or openings C C are cone-shaped and extend a little into the hollow of the shaft and are formed by a ring-shaped swelling or boss around the opening in the shaft. one end of each boltbeing threaded, whileth They form neither pockets nor passages eX- I other is provided with two wings X', Figs. (x tending' late 1ally through the shaft; and 8. he bolt-holes have two slots diainetare merely recesses open on both ends, so that through them the inside of the hollow shaft is in communication with the roasting-chambers. ln each of these recesses is inserted a cone-shaped sleeve P,

tie central shaft bv means of bolts. These sleeves form the sockets for the stirring-arms. liey are cone-shaped, with the narrow end inside the shaft. fn the upper and lower side of tiese cones is cut a groove V longitudinally, Figs. 3 to 6. grooves commence a little distance inside, so as to leave the opening on the outside of the shaft a perfect circle.

lhe stirring-arms l are hollow and closed at one end; but the end which is destined to be rieally placed and corresponding to the wings of the bolt. a new sleeve is placed into tie recess of the shaft while the furnace is hot, the nut is screwed onto the threaded end of the bolt and placed into a socket-wrench and the bolt insertel into the oit-hole of the sleeve so that the wings pass through the slots. the wings strike a projection inside, so that by further turning only the nut turns and but they tight.

In the center of the hollowsliaft is inserted an iron gas-pipe E, which is provided with pipe-fittings which permit the connection of inserted is open and shaped on the outside smaller pipes F with the vertical pipe E. like al cone and fits into the sleeve P ro the These connections are so arranged that the end of this cone aie attached two lug's V pipes F project out into the furnace through Fig 8, the position of which is ninety dethe center of each two opposite recesses. The

grecs away from the center line of the stirring-blades Uof the arm. o insert the arm, provided with a s uare iron block (ur, which ie saine is brouglit in such position that the ts into a square hole in the foot end of the lugs point up and down, while the stirringl shaft. Tiis is done to keep the pipes always blades are horizontal. By a forward movein proper position and to prevent any indenient of the stirring-arin into the sleeve the pendent movement of the same. At the top the pipe is also held in position by the socket t t iis end the provided with a stufingbox N, by which it is connected with the stationary pipe L which in turn is connected with the airpipe of a blower. Near its foot and outside the furnace the hollow shaft is provided with openings K, which serve for the admission of air into the shaft and to give access 'to the foot of the pipe E in lugs move through the grooves over the inner edge of the sleeve. Then a quarter-turn is given to the arm, by which the stirring-blades are brought to point down and are therefore in the proper position for work. Part of the inner edge of the coneshaped sleeve and corresponding to the two lugs is shaped a screw, as shown at M in Figs. 3 and 4. If, therefore,

until they pass the quarter-turn is given to the arm, the lug case of repair. The upper end of the shaft traveling' on the line of a screw will pull in enters a stack (not shown) to increase the the stirring-arm, thus producing a lit of the preventing' roaster-gas from YV hen the quarter-turn draft and to remove the heated air. To facilitate the connecting of the horizontal pipes .F with the vertical pipe E while the furnace is hot, use the bayonet-joint illustrated by ig. 9. The end of the pipe .F is screwed into a round casting Z with two Hat wings O. The fittings T of the Vertical pipe E have a recess with two grooves O'. Into this the casting end of the pipe F is inserted, and by givingI a quarter-turn a tight and rigid iit is given to the pipe.

To start operation, the stirring-arms are s ipped over the pipes F, inserted in the conical sleeve, and brought in position by giving the same a quarter-turn. Then the blower is started. The airis forced through the branch pipes F into the stirring-arms at their farthest ends, returns through the full length of t ie arms, and leaves them to enter the hollow shaft, where it unites with the upward current of air which enters at the foot of the shoulders L, formed by the screw-shaped cut in the sleeve, so that by the resistance the ore offers to the moving arm the ugs on the latter are held rigidly against the shoulders L. The ljoint just described may be termed a bayonet-joint.7 To withdraw the arm for t ie purpose of replacing the same by a new one, all that is needed is to give the arm a quarter-turn in the opposite direction and to pull the saine out of the sleeve.

As illustrated by iigz 3, the sleeve P is provided with two iianges, which are curved to comply with the rounding of the shaft and lit in a depression in the latter corresponding i l l in shape with the flanges, so that the flanges the surface of the shaft. to the shaft by f o not project above These sleeves are fastened long-handledy n ot the bolt, so that the former can be screwed ien inserted and turned, i

IOO

ITO

shaft through the openings K. By this arrangement an efficient cooling of the stirringarms, as well as of the central shaft, is obtained, which of course lengthens the life of the iron parts of the furnace and enables me to construct furnaces of a larger diameter, and consequently of larger working capacity; but the compressed air is not merely used as a cooling agent for shaft and stirrers. It is used also as a lute to prevent the loss of gas through the central shaft. As the central shaft is connected with a stack to increase the draft through it, while the roasting-shelves are connected by flues with the Glover tower and lead-chambers of an acid factory, we will find that the air in the shaft is under a much greater suction strain than the gas of the roasting-shelves. Assuming' that some of the stirring-arms do not fit tight in the sleeves, some gas will be drawn into the shaft and will be lost. In using compressed air as a cooling agent we can regulate the influx of air so as to produce an equilibrium between the suction in the shaft and the suction in the furnace, thus preventing any leakage through defective places. The same effect cannot be produced by the use of a damper in the stack of the shaft, because this would reduce the volume of air passing through the shaft to such a degree that the cooling effect would be insignificant, which would be detrimental to the life of the shaft.

In the roasting-shelves Nos. 2 and 3 the most heat is developed, and consequently in course of time the upper part of the shaft will first give out. In such a case if the shaft is one piece of casting itwould necessitate the withdrawal of the old shaft and the replacing of the same b v a new one, which is not only connected with considerable difficulties, but is also costly. To avoid this, I construct, preferably, the shaft in three sections, as illustrat-cd by Fig. l.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a roasting-furnace of the class described, a hollow shaft provided with openings or recesses, and separate cone-shaped sleeves arranged in said recesses and secured to said shaft and adapted to receive the stirring-arms.

2. In a roasting-furnace of the class described, the combination of a hollow shaft provided with openings at the roasting-shelves, sleeves fitting said openings and provided with flanges, and bolts for connecting' the fianges to the shaft, said bolts being' provided with nuts at one end and with wings at the-opposite end adapted to interlock with the shaft.

3. In a roasting-furnace of the class described, thc combination of ahollow shaft having recesses at the several roasting-shelves opening into said shaft, cone-shaped sleeves fitting in said recesses and suitably connected to said shaft, and stirring-arms fitting said sleeves, said stirring-arms having lugs and said sleeves having grooves with which said lugs interlock, said grooves commencing at a point inside the sleeve, whereby the outer end of each cone-shaped opening is circular, insuring a close fit of the stirring-arm.

4. In a roasting-furnace, the combination of a hollow shaft with recesses at each roasting-shelf, extending into the shaft, said recesses being open at both ends, cone-shaped sleeves inserted in said recesses and bolted or otherwise fastened to said hollow shaft and adapted to be withdrawn and replaced while the furnace is hot, said sleeves having one or more grooves commencing at a point inside the sleeve and extending longitudinally through the balance of the sleeve, part of the inner edge of the sleeve shaped after the line of a screw and provided with a stoppingshoulder, and stirring-arms fitting said sleeves, substantially as described.

5. In a roasting-furnace, the combination of a hollow shaft having recesses, and sleeves with spiral inner edges, with hollow stirringarms inserted in said sleeves, one end of each arm being shaped to fit into its sleeve and provided with one or more lugs placed ninety degrees off from the central line of the stirring-blades, said lug or lugs cooperating with the spiral edge of the sleeve to pull the arm tight into the sleeve,substantially as described.

6. In a roasting-furnace, the combination of a hollow shaft and hollow stirring-arms thereon, with an air-pipe, said air-pipe passing centrally through the hollow shaft and being closed at the bottom and connected at top and bottom to the hollow shaft so that pipe and shaft will rotate together without changing their relative positions, and being provided with branch pipes, said branch airpipes being provided at one end with cast-iron lugs forming bayonet-joints with recesses in fittings of the central air-pipe, said central vertical air-pipe to be connected by suitable means with the stationary pipe of a blowingmachine, substantially as described.

7. In a` roasting-furnace of the class described, the combination of a hollow vertical shaft, stirring-arms removably connected to said shaft by bayonet-joints, an air-pipe within said vertical shaft, and branch airpipes within the stirring-arms, said branch pipes being detachably connected to said main air-pipe by bayonet-joints.

8. In a roasting-furnace of the class described, the combination of a series of shelves or roasting-hearths, a` vertical hollow shaft, hollow stirring-arms connected to said shaft, a vertical air-pipe centrally located in said shaft, and branch air-pipes located in said IOO IIO

stirring-arms, said hollow slml't having oponl In testimony wheroofl have. signedmy mm1@ mgs at top und bottom to provldo for :L draftl to thls speollczrtlon in tho` presence of two Subthorotlu'ough, and sind branch alr-plpes bolug sorlblng wltuossos.

arranged to discharge into tho outer ends of UTTOKAR HOFh/IANN. 5 sand stirr1ng=arm$, tho air so dlsohzu'g'od pass- VVltnoSses:

ing through the sturing-mms to the vertical C. A. PROBST,

hollow shaft. "WAL MIDDLEKAUFI.1 

